Digital operator



Jan. 24, 1967 R, w. HATCH, JR 3,300,176

DIGITAL OPERATOR Filed June 24, 1964 DIGITAL PULSE IN BLEED 2o POWER a h g FIG. 11

2O INVENTOR.

RICHARD W. HATCH, JR.

AGENT United States Patent 3,300,176 DIGITAL OPERATOR Richard W. Hatch, Jr., Norwell, Mass., assignor to The Foxboro Company, Foxboro, Mass., a corporation of Massachusetts Filed June 24, 1964, Ser. No. 377,611 1 Claim. (Cl. 25133) This invention relates to digital devices and has particular reference to fluid operated devices such as valves, transducers, and relays.

As an illustration of this invention, a device is provided in the form of a double acting unit operated through a nozzlebaflle unit formed by a diaphragm movable restrictively against a nozzle. In a specific rform this diaphragm is snap-acting.

A digital operator according to this invention may be a small device which provides digital relay, valve, or transducer action from small signals, on a substantial frequency basis. Thus a very compact, sensitive, yet rugged, device is provided.

It is therefore an object of this invention to provide a new and improved fluid operator.

Other objects and advantages of this invention will be in part apparent and in part pointed out hereinafter and in the accompanying drawings, wherein:

FIGURE I is a front elevation of a fluid operator device according to this invention;

FIGURE II is a plan view of the structure of FIGURE I; and

FIGURE III is a vertical central section of the device of FIGURE I.

Referring to FIGURE IH, this unit comprises a main body which is made up of a top unit 11, a central unit 12, and a bottom unit 13. These units are held together by vertically disposed corner screws as indicated at 14.

The input to this device is at the top thereof as at in the form of a digital fluid pulse input from whatever measurement or operational source is desired. The output is in terms of the vertical movement of a shaft 16 at the bottom of the unit. This vertical movement may result in fluid fiow-pressure output as indicated by arrows 17, or the output may be a mechanical action of the movable shaft 16 upon an electrical microswitch as at 18. These ouputs may be used in combination if desired.

The unit is provided with two short cylindrical chambers of substantial radius. One of these is in the top portion 11 at 19, and the other is in the central portion 12 at The upper chamber 19 has its upper end closed off by a rigid type snap-action diaphragm 21. As the digital pulse is entered at 15 it is applied to the upper surface of the snap-action diaphragm 21. This causes the central portion thereof to snap downwardly a short distance to close off a fluid nozzle 22. This nozzle extends vertically upward into the upper chamber 19 in alignment with the digital pulse input 15. Thus each input pulse closes off the nozzle 22 and in between adjacent pulses the snap-acting diaphragm 21 snaps back upward to its normal position.

Chamber 19 is supplied with fluid flow pressure from a common power input 23 and through a branch power input 24 leading past an adjustable screw threaded restricter 25 and upward to the nozzle 22. A bleed outlet is provided at 26 from the upper chamber 19 so as to provide a flow through the system which is interrupted when an input digital pulse causes a back pressure in the nozzle system by closing off the nozzle 22 with the snap-acting diaphragm 21.

This back pressure is app-lied to the lower chamber 20 through a downward passage 27. A transverse flexible diaphragm 28 closes off the bottom portion of the chamber 20 and is movable by such back pressure. The shaft 16 is secured centrally of flexible diaphragm 2-8. This back pressure on the nozzle 22 causes the diaphragm 28 to move downwardly and consequently results in the vertical movement of the shaft 16.

Power is also supplied from the source 23 through a lower input 29 into the central chamber 30' and upward through passages 30" to the underside of the diaphragm 28.

The lower face of the section 13 is provided with a recess 31 with a downwardly facing valve seat 32'therein. A valve disk 33 is mounted on the shaft 16 and seats on the valve surface 32.

When the shaft 16 is moved downward, power from the source 23 is supplied through the inlet 29 downward past the valve seating disk 33 into a pressure flow outlet as indicated by the arrows 17. A suitable matching chamber (not shown) can be provided in this outlet to properly collect this output fluid flow into a pipe as indicated by the dotted line 34, which may lead to a valve 35 operatable to vary the flow in a line 36. The power is provided with passage 37 from the chamber 30' to the recess 31. This is not an operating force against the disk 33 of any substantial proportion as may be noted from the relatively small diameter of the passages 37. This power is the operating output when it is allowed to pass the disk 33 when the shaft 16- has moved downward to open a passage between the face 32 and the top of the disk 33, into the main recess 31.

This invention therefore provides a new and improved fluid operator which uses a digital pulse input to provide a power or movement output. This is a sensitive, small, compact device.

As many embodiments may be made of the above invention, and as changes may be made in the embodiments set forth above without departing from the scope of the invention, it is to be understood that all matter hereinbefore set forth or shown in the accompanying drawings is to be interpreted as illustrative only and not in a limiting sense.

I claim:

A digital fluid operator wherein on-off operation of a fluid power stream is accomplished by fully snap-acting diaphragm-nozzle means responding to fluid pulse input to activate a power valve,

said operator comprising, in combination,

a pulse signal input, a snap-acting diaphragm against one side of which said input pulse is applied, a nozzle chamber in which said diaphragm moves in its snapaction, a nozzle directed into said nozzle chamber on the other side of said snap-acting diaphragm and positioned and located to be restricted by said snapacting diaphragm. as the diaphragm is so moved in response to said input pulse, a bleed vent from said nozzle chamber to atmosphere,

a fluid power supply passage to said nozzle whereby a continuous fluid flow is provided through said supply passage to said nozzle and from said nozzle into said nozzle chamber and to atmosphere through said vent,

a variable restrictor in said nozzle power supply passage,

a valve operating chamber, a fluid passage operating connection from said valve chamber to said nozzle power supply passage past said variable restrictor, whereby adjustment of said variable restrictor simultaneously changes the fluid supply to said nozzle and to said valve chamber,

a flexible diaphragm across said valve chamber such that said nozzle fluid supply is applied to one side of said flexible diaphragm, with movement producing effect on said flexible diaphragm from. back pressure from said nozzle when said nozzle is restricted by said snapacting diaphragm,

a shaft secured to said flexible diaphragm and extending therefrom on the other side of said flexible dia- 5 References Cited y the Examiner phragrn, a valve closure on said shaft, 21 valve seat UNITED A S PATENTS for said closure,

a power fluid chamber about Said S fluid Passages 1 3? 551 2 from said power fluid chamb r t Said Valve Operating 10 5/ 32 B 11.16 u 251 33 X chamber on said other sid f Said fifiXible diaphragm, 2O70421 2/ 1 37 i 1 2 5 1 75 further fluid passages fr m Said Power fluid Chamber 5 3 0 1952 l o 251 75 to said valve closure when said closure is resting 1 5 1 5 l ag1o u on said valve Seat, 9 8 Dyson 25133 a fluid power supply passage to said power fluid chamber, and a power fluid exit chamber containing said valve seat and said valve closure,

whereby power fluid flow is produced from said last named fluid power passage, through said power fluid 15 ALAN CO-HAN, Primary Examiner.

M. CARY NELSON, Examiner.

J. W. KNIGHT, Assistant Examiner. 

